Effect of natural and synthetic antioxidants on protein oxidation and colour and texture changes in refrigerated stored porcine liver pâté

The antioxidant effect of two plant essential oils (sage and rosemary) and one synthetic antioxidant (BHT) on refrigerated stored porcine liver paté (4°C/90 days) was evaluated. Patés with no added antioxidants were used as controls. Liver patés were analysed for protein oxidation, modification of heme (HI) and non-heme iron (NHI) concentrations, and colour and texture characteristics at days 0, 30, 60 and 90 of refrigerated storage. The amount of carbonyls from protein oxidation significantly (p<0.05) increased during refrigerated storage, and this increase was significantly higher in the control patés than in their treated counterparts. Antioxidants successfully protected heme molecules from degradation and significantly inhibited the increase of NHI in refrigerated stored liver patés. Colour changes seemed not to be directly related to oxidative processes since patés with added antioxidants suffered greater colour modifications than the controls. The addition of rosemary essential oil significantly reduced hardness of liver patés. Sage and rosemary essential oils exhibited similar antioxidant properties to BHT denoting their suitability as alternatives to synthetic antioxidants.     

Effect of varying oxygen concentrations on the shelf-life of fresh pork sausages packaged in modified atmosphere

A total of 105 fresh pork sausages were packaged in atmospheres varying in oxygen concentration, using the following mixtures (%O₂/%CO₂/%N₂): 0/20/80, 0/20/80 + O₂ scavenger, 20/20/60, 40/20/40, 60/20/20, and 80/20/0. In addition, two batches were subjected to vacuum packaging or over-wrap with O₂-permeable film. They were stored for 20 days at 2 ± 1 °C in the dark. Values of pH, CIE L*, a* and b* color parameters, surface metmyoglobin percentage, TBA-reactive substances, psychrotroph aerobe bacterial numbers and sensory discoloration and off-odor were assessed throughout storage. Packaging in the absence of O₂, either under vacuum or in atmosphere with O₂ scavenger, led to extension of shelf-life in terms of both color and odor stability due to low oxidation rates. Increase of O₂ caused a significant enhancement of oxidation, decrease of shelf-life due to discoloration and off-odor development. The highest O₂ concentration gave rise to a significant color improvement, though only for a limited period of 8 days.     

超声波辅助淀粉双酶水解技术及其机理

为了探索超声波对淀粉液化和糖化酶解过程的影响及其机理,以液化值和葡萄糖当量值(DE)为指标,探讨了超声波功率、超声时间、淀粉乳浓度对淀粉酶解过程中还原糖产率的影响。结果表明:在超声功率100 W,超声时间10 min,淀粉乳浓度20%的条件下,淀粉乳的液化值及DE值从未处理样品的19.89mg/mL、82.06%分别提高到30.67 mg/mL、94.30%。超声波处理,使得淀粉颗粒表面的凹痕和裂痕明显增多,淀粉结晶结构遭到破坏,红外结晶指数下降,淀粉支链结构破坏,直链淀粉含量增加,溶解度提高了246.8%。此外,超声波处理对酶的激活作用使得α-淀粉酶活力提高了15.29%。     

新型引发体系对淀粉接枝共聚反应的影响研究

为探讨新型引发体系对淀粉接枝共聚反应的影响,以玉米淀粉为原料,采用过硫酸铵-亚硫酸氢钠引发体系合成了淀粉接枝丙烯酸丁酯共聚物,确定了丙烯酸丁酯浓度、引发剂浓度、过硫酸铵与亚硫酸氢钠间摩尔比、反应温度、反应时间等工艺条件.并通过红外光谱、X-射线衍射仪和扫描电子显微镜对共聚产物结构进行了表征.过硫酸铵-亚硫酸氢钠引发体系可有效降低接枝共聚反应的活化能,从而降低反应温度,且该接枝淀粉的合成工艺简单,成本较低.     

淀粉的老化机理及抗老化研究

对谷物淀粉的理化特性进行了研究,分析了淀粉的老化机理及老化模型.根据淀粉的特性,选用酶制剂、乳化剂和胶体等作为抗老化剂用于谷物食品保鲜,能有效延长食品的货架期.     

不同抗氧化剂对辐照扒鸡脂肪氧化的影响

本文研究了VC、VE、BHA三种抗氧化剂以及由它们组成的复配抗氧化剂对真空包装辐照扒鸡中脂肪氧化的影响。通过对添加抗氧化剂的辐照扒鸡的过氧化值测定,比较了三种抗氧化剂的抗氧化效果。试验结果表明:添加抗氧化剂可以显著降低辐照扒鸡的过氧化值;单一抗氧化剂以添加0.02%的BHA效果较好;复配抗氧化剂的抗氧化效果优于单一抗氧化剂,复配抗氧化剂以添加0.02%VC、0.01%VE、0.02%BHA效果较好。     

常用淀粉对甘薯粉糊化特性的影响

利用Brabender粘度仪考察了几种常用淀粉对甘薯粉糊化特性的影响，认为马铃薯、甘薯淀粉使甘薯粉糊化温度降低，玉米、木薯淀粉则使其升高；甘薯、玉米淀粉使甘薯粉糊化时间延长。添加各种淀粉均可使甘薯粉的峰谷粘度提高；马铃薯、玉米淀粉还可大幅度提高其峰值粘度。但马铃薯淀粉粘度破损值大，玉米淀粉破损值小、峰谷粘度高。     

常用淀粉对甘薯食品膨化质量的协同作用研究

纯甘薯制品膨化质量差，适量添加淀粉可显著提高膨化度、改善产品质构。本文以常用的高温膨化方式，考察了马铃薯、木薯、甘薯及玉米淀粉对甘薯制品膨化度和感官质量的协同作用。结果表明，以鲜甘薯质量为基准计的最佳工艺配方为：马铃薯淀粉20％、木薯淀粉5％、玉米淀粉10％。淀粉对甘薯膨化食品的影响显著性顺序为，马铃薯淀粉＞木薯淀粉＞玉米淀粉。其中马铃薯淀粉的影响极显著，而木薯、玉米淀粉的影响相对不显著。     

罗汉果块根淀粉的提取及其性质研究

本文以罗汉果块根为原料，提取并纯化其淀粉，并对淀粉的含量、淀粉中还原糖的含量、以及淀粉的溶解度、糊的透明度、糊的沉降性质等进行了研究，结果表明：纯淀粉含量为30.89%（以2年生干根计），淀粉的白度为94.5%，发展前景十分广阔。     

修饰预糊化木薯淀粉性能研究

介绍了经化学修饰后再进行预糊化制备得到的修饰预糊化木薯淀粉的性能，并与国产预糊化木薯淀粉和泰国泰花牌预糊化木薯淀粉的性能进行了比较。结果表明：修饰预糊化木薯淀粉的性能达到且超过泰国泰花牌预糊化木薯淀粉的性能，远远优于国产预糊化木薯淀粉。